You need to read the article very well, checking the address and sending to right address only applies to some cases. What about sending USDC to USDT address on an exchange that support USDT but do not support USDC? If the amount is not high enough, all what the customer care will message the person is that it is not possible to recovery the coin, that it does not meet the requirements needed. Do you know that ERC20 USDT and USDC have the same address which is ethereum address, but because USDC is not supported by the exchange is the reason for the loss, but I'm this can not happen of you have the ethereum private key.

Also check this:
The smart contract
The altcoins are getting more complex and complicated for users with the introduction of some particular smart contract like the binance smartchain. Binance smartchain (BSC) addresses are the same as ERC20 tokens addreses, while some people will confuse it with Binance chain addresses (addresses that start with bnb), this has caused great losses for users. See the illustration below as a good example.

Exchange A support Coin A
Exchange B support Coin A
Coin A support ERC20 and BSC on Exchange A
Coin A support ERC20 but do not support BSC (Binance smart chain) on Exchange B

Because BSC addresses are like ERC20 addresses, if the sender send Coin A (BSC type) into an exchange (exchange B) that do not support BSC but support ERC20 for the coin, this will lead to loses. Only what can make the owner not to lose is to have the private key that can be used to recover the coins. Some exchanges can help too, but if low amount is lost, no help will be rendered.